Refrigerating apparatus



I. MITCHELL REFRIGERATING APPARATUS April 6 1926.

1919 5 Sheets-Sheet 1 Original Filed August April 6 ,1926. 1,579,451

A. l. MITCHELL REFRIGERATING APPARATUS Original i August a. 1919 s Sheets-Sheet 2 v 7 1,579,451 l. MITCHELL REFRIGERATINQ APPARATUS Filed Augus a. 1919 5 Sheets-Sheet 4 7Z ve7ZZ J7?.

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April 6 1926.

Patented Apr. 6, 1926.

Y UNITED STA TES PATENT OFFICE.

' ALEXANDER I. MITCHELL, OF WILMINGTON, MASSACHUSETTS, ASSIGNOB, B Y MESNE ASSIGNMENTS, TO STONE & WEBSTER, 1110., A CORPORATION OF MASSACHUSETTS.

REFRIGERATING APPARATUS.

Application filed August 8, 1919, Serial No. 316,061. Renewed. April 4,1925.

To all whom it may'coowern:

Be it known that I, ALEXANDER I.M1TOH- ELL, a citizen of the United States, residing at Wilmington, county of Middlesex, and

5 States of Massachusetts, have invented certain Improvements in Refrigerating Appa-- ratus, of which the following description, in connection with the accompanying drawlngs, is a specification, like reference charac l ters on the drawings indicating like parts in the several figures.

ThlS invention relates to a refrigerating apparatus and is concerned particularly with refrigerators intended for domestic use 15 in which refrigerating action is produced without the aid of ice. In my co-pending application Serial No. 316,060 filed concurrently herewith I have disclosed a refrigerating apparatus of this type in which the 0 refrigerating action is produced through the will be particularly pointed out in evaporating effect of a current of air on a body of liquid. So far as the object of maintaining the food compartment or compartments in the refrigerator at the desired low temperature is concerned, it is unnecessary in this apparatus to form ice. It is, howbodied in many other forms and be used' independently of other refrigerating apparatus. The invention will be readily understood from the following description when read in connection with the accompanying drawings and the novel features the ap' pended claims.

Referringto the accompanying drawings,

Figure 1 is a view, partly in vertical cross section and partly in front elevation, .showing a refrigerating apparatus to which I the present invention is applied;

Fig. 2 is a'vertical cross sectional view at I right angles to the View shown in Fig. 1;

Fig. 2 is a cross sectional view through a portion of the upper'header of the heat absorbing unit;

Fig. 3 is a horizontal cross sectional view substantially on the line 33 Fig. 2;

Fig. 4 is a horizontal cross sectional view substantially on the line 4-4, Fig. 2;

Fig. 5 is a front elevation of the ice bottle and the parts that support it;

Fig. 5 is cross sectional view through the valve at the top of the ice bottle;

Fig. 6 is a side view of the apparatus shown in Fig. 5;

Fig. 7 is a vertical cross sectional view through the lower part of an ice bottle similar to that shown in Figs. 5 and 6; and

Fig. 8 is a horizontal cross sectional view on the line 88, Fig. 7. 1

It is well understood by those skilled in this artthat the evaporation of water produced by some means. other than by the application of heat results in absorbing heat from the body of water due tn the latent heat of vaporization. The water may be evaporated in many ways, as, for instance, by reducing the pressure on it, blowing a current of air across its surface, or utilizing the affinity of some chemical for water vapor. In the refrigerating apparatus illustrated in the accompanying drawing, the refrigerating effect is produced by reducing the pressureon the body of water to be cooled and utilizing a current-of air to pick up and carry away water vapor from this body of water. The same process is utilized n the present invention.

The apparatus shown comprises a suitable heat insulating casing 1, the walls of the casing being double and the space between them being filled with ground cork, asbestos, mineral wool, or, any other suitable heat insulating material. Access to the interior of the casing is provided by 'doors, one of which is indicated at 2. -Within the caslng is a food. compartment having suitable shelves 3. A heat absorbing unit 4 is also located within the casing, this unit consisting of a water container having an upper header 5, a lower header 6, and a series of vertical tubes or pipes 7 that connect the two headers. a series of blocks 8 which space the umt from the bottom of the chamber in the casing. Preferably the upper header 5 has This unit rests on a series of vertical tubes extending therethrough, as shown in Fig. 4, to provide increased heat absorbing surface. A drain pipe 9 leads from the lower header 6 through the bottom of the casing 1 and normally is closed by a cap 10. This unit is partially filled with water, as shown in the drawings, the height of the water being indicated by a water gage 11.

A partial yacuum is maintained in the container 4 above the surface of the water therein by means of an exhaust apparatus comprising a pump 12, theintake side of which is connected with the upper part of the unit 4 by a pipe 13. Any suitable form of pump may be used but the form illustrated has proved very satisfactory and therefore is preferably employed. This pump comprises a rotor'14 mounted within an eccentric chamber 15 formed in a suitable casing. The rotor contains four blades 16 which are mounted to slide radially in suitable slots or formed in the rotor, these blades being spring pressed outwardly so that their outer edges are held constantly in engagement with the peripheral wall of the chamber 15. This wall is eccentric to the rotor from a point substantially at a and proceeding in the direction of rotation indicated by the arrow, to another point approximately as indicated 'at b; but between the points a and b the chamber is concentric with the rotor and is in contact therewith. The air enters the pump in the neighborhood of the point a and is exhausted or forced out of the chamber 15 through the pipe 16 in the neighborhood of the point 6. The pump rotates in a bath of oil and provision is made, as is usual in this style of pump, for the entrance of a very small quantity of oil to the pump for lubricating and sealing purposes. Consequently, the construction of chamber just described provides a long sealing surface between the points I) and a which substantially reduces the leakage that otherwise would take place in the pump.

A check valve 17 is'connected into the outlet pipe 16 and this pipe 16 discharges into a receptacle 18 which catches any oil that may be carried over and also serves as a muflier. The pump preferably is driven very slowly, say, for instance 60 revolutions per minute, and is operated by an electric motor 19 belted to a pulley 20 which operates through the reduction gears 21 to drive the pump.

When the apparatus is in operation the pump will exhaust the air and a certain quantity of water vapor from the space above the level of the liquid in the container 4. The reduction of pressure above the surface of the water will cause more of the water to vaporize thus lowering the temperature of the body of waterin the unit 4. After a relatively short time, however, the maximum vacuum of which the apparatus is capable is produced'and thereafter the vaporization takes place at only a relatively slow rate,too slow to produce the desired refrigerating action economically. The rate at which heat is absorbed will vary directly with the rate at which the water in the unit 4 is evaporated, and I have discovered that the rate of vaporizzn tion can be greatly increased by providing a leak, so to speak. That is, means is pro vided for admitting a limited quantity of air into the unit.

This means consists of a pipe 22 leading from a point in the food chamber of the refrigerator downwardly through the top of the container to a point in the water close to the bottom of the header 5. A valve is connected in this pipe and is adjustable to determine the rate at which air will be admitted into the container. Inasmuch as the air enters the heat absorbing unit at a point below the surface of the water it comes into very intimate contact with the water and thus becomes heavily laden with water vapor. The apparatus therefore operates to draw continuously from the container 5 a current of rarefied air, laden with water vapor, and thus to produce a rapid evaporation of the water and consequently a rapid cooling action. The reduction in temperature of the body of water in the heat absorbing unit obviously operates to absorb heat from the food chamber and thus to keep it at the desired low temperature. The apparatus so far described is like that shown'and described in my co-pending ap plication above referred to.

The apparatus provided by the present invention comprises a container or bottle 25 which may be removably supported .in the casing 1 by a fixing or fitting 26. This bottle consists ofa tapered metallic shell having a removable head or cover 27 secured to its lower end by a series of swinging bolts 28. Each bolt is provided with a thumb nut 29 and the bolts are mounted to swing into slots formed, respectively, in brackets 30 secured to the cover. The thumb nuts are then screwed up to draw the head or cover 27 snugly against the lower end of the bottle 25, a rubber gasket 31, Fig. T, being interposed between these parts to form a tight joint. This bottle thus provides a convenient container for water and ice. cream, or any liquid that is desired to be chilled or frozen.

A certain amount of air; leaks into the food chamber around the door and an air in let pipe 33 also is provided which extends through the top of the casing 1 into a box 34 that is filled with cotton, charcoal or other suitable air filtering material. Openings are made in this box to admit air there-,

.faced with rubber. A spring 38 secure to. The lower end of the pipe.33, as best shown in Fig; 6, is connected by a rubber or other flexible connector 35 to a curved tip 36 having a vertical disposed head 37 at one I1(l 't0 the fixture 26 bears against the head 37 and tends to force it to the left, as the parts are seen in Fig. 6. Usually the end of this pipe is open at the head 37 so that the air is free to travel downwardly through the pipe 33 into the food chamber from which it'is .later withdrawn either through the pipe 22 or through the inlet '40 of a valve casing 41 which is provided with a needle valve 42 to control the flown-f air 5 and then extends downwardly into the header to apoint near the lower end of the header so that the air admitted to the header through thls pipe will be conducted ,to a point always below the level of the water inthe cooling unit.

The fitting 26 is so constructed that it will removably support the bottle 25 and it .is also provided with a valve which is automatically operated upon the mounting of the bottle therein to connect the bottle in the air circuit just described.

For this purpose the upper end of the bottle is provided with two pins extending oppositely therefrom, one of these pins being shown at 45 in Figs. 5 and 6, and th fitting 26 is provided with a depending tubular flange 46 in which two bayonet slots are formed, one of these slots being shown at 47. The fitting 26 also is provided with a tapered valve plug 48, and a tubular flange or sleeve 49 is secured to the lower end of this plug.- The sleeve 49 lies immediately within the circular flange 46 and a skirt 49 is provided with two vertical slots to receive the pins 45, one of these 'slots being indicated at 50 in Fig. 6. The valve 48 also carries a central stud or projection 51, Fig. 5, which is surrounded by a 'rub- 'ber gasket 52 of a suitable size to fit snugly into the top of'the bottle 25. A hole 53 is drilled centrally in the port 51 into the body of the plug, as shownin Fig. 5,"and another hole 54 3 is drilled laterally into the hole 53 to afford communication withv a passage. 55 formed in the fitting 26, the latter passageopening into the pipe. 43. i

In order to mount the bottle .25 in the fitting 26, the pins 45 are slipped into the slots 50 and 47 at the opposite sides of the flange 46, each slot 50 registering with the vertical part of its cooperating bayonet slot 47. After the bo'ttle.25 has been moved upwardly until the pins 45 come in line with the horizontal portions of the bayonet slots, it is then turned toward the right until the'pins arrive at the ends ofthe horizontal portions of the bayonet slots. It .is obvious that the bottle then is supported by thefitting 26 and that it will remain in this position until removed again by reversing the operations just described.

It will be seen that the operation of placing the bottle 25 in the position just described will turn the valve plug 48 in the fitting 26 and bring the port 54, Fig. 5, into registerwith the assage- 55. This movement of the valve p ug 48 also turns the port or duct. 56, Fig. 5, out of communication with the air passages 57 and 57 with which it normally communicates and through which the air that is admitted to the valve 41 passes on its way to the passage '55.

The bottle 25 is provided with a valve casing 58 having a side inlet fitting 59, Fig. 6, which contacts with the rubber face of the head 37 at the lower end of the air inlet pipe 33 when the bottle is placed in its operative position in the fitting 26. The spring 38 holds the part 37 firmly against the member 5.9. A needle valve 60 controlsthe flow of air through the valve casing 58 and a pipe 61 conducts the air thus admitted to a header 62 formed at the lower end of the bottle 25, as'best shown in Figs. 6, 7 and 8. A series ofsmall holes 63 are drilled through the wall of the bottle into this air header. Consequently when the bottle has been placed, as shown in Figs. 5 and 6, the air passes down through the pipe '33, through and 55 into the container 5, from which it is withdrawn 'by means of the pump. 1

It .is obvious that the liquid in the bottle will be under substantially the same degree of vacuum as thewater in the container 5,

and the air traveling through the water in the bottle will pick up water vapor until it becomes practically saturated. The evaporation of the liquid in the bottle thus produced will cool the liquid, as above described, and this cooling action may be continued until all the liquid in the bottle is frozen. I have found by actual use of the apparatus that it is entirely possible to freeze ice cream,

sherbets and other frozen foods as well as to freeze water.

' Inasmuch as it is desired to reduce the temperature of the liquid in the bottle to a point considerably below that of theatmosphere surrounding the bottle, I prefer to, 0

heat insulate the bottle in some manner and this obj ect may conveniently be accomplished by makingthe wall of the bottle double, as shown in Fig. 7, and evacuating the space between the walls. j

,When the liquid in the bottle has been frozen or chilled to the desired degree, the bottle may then be remove'd'simply by turning it toward the left until the pins 45 come in register with the vertical parts of the bayonet slots 47 when the bottle is lowered, thus moving it out of contact with the fitting 26. This movement also carries the air intake member 59 away from the connection 37 so that the air circuit through the bottle is interrupted. At the same time it turns the valve plug 48 back to bring the port 56into communication with the ducts 57 and 57 and thus re-establishes the air circuit through the valve 42. This movement of the plug 48 also closes the port 54.

As shown in Fig. 5, the valve plug 48 is tapered and it is yieldingly held in its seat by aspring hearing against a nut 66 which is screwed on the stem 67 that projects upwardly from the plug 48, the spring resting against a washer which bears on the upper surface of the fitting 26.

After the bottle has been removed from the casing the cover is taken off and the contents of the bottle if frozen can be conveniently removed by dipping the bottle for an instant in warm water which will melt the 'frozen body adjacent to the wall of the bottle and allow the contents to slide out.

WVhen the refrigerating apparatus is operating Without the bottle the fact that the air inlets 22 and 42 are positioned in the food chamber at widely separated points creates an active circulation of the air in the chamber and thus prevents the accumulation of food odors.

The apparatus operates at its maximum efficiency when the air after flowing through the container 25 is substantially saturated. This condition is produced by operating the apparatus at a fairly high vacuum and by the fact that the orifices through which the air is admitted to the liquid in the bottle are located close to the bottom of the bottle and consequently well below the surface of the water. Furthermore, the fact that these orifices are. small so that the air entering the container at any instant is split up into several small bubbles instead of being present in a single large bubble, tends to realize a complete saturation of the air. It should be noted that free air is taken. into the apparatus That is, the air entering the pipe 33 is thewhich I am at present aware, it is obvious that-the invention may be embodied in many forms other than that shown and that many changes may be made in the apparatus shown out departing from the spirit or scope of this invention.

What is claimed as new is: l. A refrigerating apparatus comprising a liquid container, means for removably supporting said container in an upright position, the walls of said container forming a hollow air containing space at the lower end of said container, a series of apertures leading from said space intothe liquid containing space in said container, means for maintaining a partial vacuum in said container above the surface of the liquid therein, and connections for conducting free air into said space in the bottom of said container.

A refrigerating apparatus comprisinga liquid container, means for maintaining a partial vacuum in said container above: the

surface of the liquid therein, means for admitting air at a limited rate into said container, means for removably supporting said container in its operative position, and valve means arranged to be operated automatically by the mounting and dismounting of said container on its support to connect it with and disconnect it from said vacuum producmg means.

3. A refrigerating apparatus comp-rising a casing having a food compartment therein, a heat absorbing unit mounted in said casing in communication with said compartment, said unit comprising a container having aliquid therein, means for maintaining a partial vacuum in said container above the surface of the liquid therein, connections for conducting free air into said container, a second liquid container, means for removably supporting said second container, and a valve operated automatically by the mount-- ing or dismounting of said second container on its support to connect or disconnect said container with said air conducting means to cause a current of air to pass through said second container.

4. A refrigerating apparatus comprising a casing having a food compartment therein, a heat absorbing unit mounted in said casing in communication with said comp-artment, said unit comprising a container having a liquid therein, means for maintaining a partial vacuum in said. container above the surface of the liquid therein, connections for conducting air from said compartmentinto said container, additional connections for conducting air into said container, and a second liquid container, said additional con nections including valve means operable to connect or disconnect said second container into the air circuit.

5. A refrigerating apparatus comprising a casing having a food compartment therein,

a heat absorbing unit mounted in said casing in communication with said compartment, said unit comprising a container having a liquid therein, means for maintaining a partial vacuum in said unit above the surface of the liquid therein, connections for conducting free air from a point outside of a partial vacuum in said container above.

the surface of the liquid therein, connecttions,for conducting air at a limited rate into the li uid in said container, a second container or a liquid to be chilled, and means for removably connect-ing said second container into said air conducting connec tions to maintain a partial vacuum in said second container and to cause air to pass through said second container.

7. A refrigerating apparatus comprising a casing having a food compartment therein,-

a heat absorbing unit mounted'in said casing in communication with said compartment, said unit comprising a container having water therein, means for maintaining a partial vacuum in said container above the surface of the water therein, connections for conducting air at substantially atmospheric pressure into the water in said container, means for filtering the air so conducted into the container, a second liquid container, means for removably supporting said second container in its operative position, and devices whereby said second container when in its operatlve position may be connected into said air conductlng connections to cause air from said filtering means to pass through both containers.

8. In a refrigerating apparatus, the combination of a container for a liquid to be chilled, means for removably supporting said container during the process of chilling said liquid, said means including a fitting arranged to be connected to said container above the surface of the liquid therein, an

exhaust pump, and connections between said exhaust pump and. said fitting for maintaining a vacuum in said container above the liquid therein, said containerbeing con-M structed to admit free air into said liquid near the bottom of the container. I

9. In a refrigerating apparatus, the combination of a container for a liquid to be chllled, means for removably supporting said container in an upright position, said means including a hollow fitting with which the upper end of the container is constructed to connect, an exhaust pump, connection between said exhaust pump and said fitting for exhausting air from the fitting and from the portion of said container above the liquid therein, said container having a hollow air containing space at its lower end and a series of apertures leading from said space in said container, and means for conducting air into said air space at the bottom of said bination of an exhaustpump; air connections leadin to the intake of said pump; a hollow fitting in communication with said connections; a container for liquid to be chilledhaving an open end constructed and arranged for connection with said fitting whereby said pump may operate to exhaust air from said container; and an air connection associated with said fitting and constructed and arranged to'admit air at a restricted rate to the lower part of said container when the latter is connected with said fitting.

12. In a refrigerating apparatus, the combination of a heat insulated casing enclosing a food compartment; a heat absorbing unit mounted in said compartment in heat absorbing relation thereto, said unit including a container for liquid; .a pump connected with said container and serving to maintain a partial vacuum within the container above the surface of liquid therein; connections for conducting air at a limited rate into the liquid in said container;-a second container for liquid to be chilled; means for releasably connecting said second container with the intakeof said pump whereby said pump may exhaust air from second container; and valve means controlling 'communication between said second container and said pump.

In testimony whereof I have signed my name to this specification.

ALEXANDER IpMlTCfiELL.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,579,451, granted April 6, 1926, upon the application of Alexander 1. Mitchell, of \Vilmington, Massachusetts, for

an improvement in Refrigerating Apparatus, errors appear in the printed specification requiring correction as follows: Page 2, line 31, for the words approximately as indicated read indicatedapprow'imately' page'3, line 4, for the word vertical read vertically, and line 51, for port read part; page 4, line 25, after the Words bottle and frozen insert a comma; page 5, claim 9, after line 77 insert the words into the liquid containing space; same page, line 116, claim 12, before the Word f liquid insert the article the; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflicer Signed and sealed this 11th day of May, AD. 1926.

[snAL] M. J. MOORE, v I Acting Commissioner of Patents; 

